And now, a new twist in the lance armstrong saga, stripped of his medals, confessing to oprah. And tonight, word that criminal charges hang in the balance. It's an abc news exclusive, and abc's neal karlinsky, who first broke this story, tells us what's looming. Reporter: Tonight, abc news has learned lance armstrong -- last seen publicly with his girlfriend and family boarding a plane in hawaii -- is in the crosshairs of federal criminal investigators. According to a high level source, agents are actively investigating armstrong for obstruction, witness tampering, and intimidation, for allegedly threatening people who dared tell the truth about his cheating. A se reignited by his recent confession to oprah. I didn't invent the culture. But I didn't try to stop the culture. Reporter: If charges are ultimately filed, the consequences could be severe. These are serious potential crimes. You talking about possible sentences of up to five, ten years, if convicted. Reporter: And tonight, one more harsh deadline. He must tell all under oath to anti-doping authorities or lose his last chance at reducing his lifetime sporting ban. He ises no expected to cooperate. Neal karlinsky, abc news, seattle.

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